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chore: turn off [Inhabited β] : Inhabited (Sum α β) #5270

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chore: turn off [Inhabited β] : Inhabited (Sum α β) #5270

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chore: turn off [Inhabited β] : Inhabited (Sum α β)
kim-em Sep 6, 2024
25eb95c
make reducible
kim-em Sep 6, 2024
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11 changes: 8 additions & 3 deletions src/Init/Core.lean
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Original file line number Diff line number Diff line change
Expand Up @@ -165,9 +165,13 @@ inductive PSum (α : Sort u) (β : Sort v) where

@[inherit_doc] infixr:30 " ⊕' " => PSum

instance {α β} [Inhabited α] : Inhabited (PSum α β) := ⟨PSum.inl default⟩
instance instInhabitedPSumLeft {α β} [Inhabited α] : Inhabited (PSum α β) := ⟨PSum.inl default⟩

instance {α β} [Inhabited β] : Inhabited (PSum α β) := ⟨PSum.inr default⟩
/--
`PSum α β` is inhabited if `β` is inhabited.
This is not an instance to avoid non-defeq instances.
-/
def instInhabitedPSumRight {α β} [Inhabited β] : Inhabited (PSum α β) := ⟨PSum.inr default⟩
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/--
`Sigma β`, also denoted `Σ a : α, β a` or `(a : α) × β a`, is the type of dependent pairs
Expand Down Expand Up @@ -1153,7 +1157,8 @@ variable {α : Type u} {β : Type v}
instance Sum.inhabitedLeft [Inhabited α] : Inhabited (Sum α β) where
default := Sum.inl default

instance Sum.inhabitedRight [Inhabited β] : Inhabited (Sum α β) where
/-- This is not an instance to avoid non-defeq instances. -/
def Sum.inhabitedRight [Inhabited β] : Inhabited (Sum α β) where
default := Sum.inr default

instance {α : Type u} {β : Type v} [DecidableEq α] [DecidableEq β] : DecidableEq (Sum α β) := fun a b =>
Expand Down
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